Celebrities, fashion designers and the lords and ladies of finance gathered Monday evening for the Metropolitan Museum of Art's annual gala. The red carpet scene is akin to the Oscars, and this year's celebration of designer Charles James and ball gowns certainly brought out the best of glam.

Beyoncé in Givenchy.

Sarah Jessica Parker in Oscar de la Renta.

Vogue editor Anna Wintour in Chanel.

The evening had all the trappings of a Cinderella fairy tale. But for an increasing number of women, ball gowns and couture clothing are more than an indulgence for one night only.

Buying clothing is now an investment, much like art or collecting classic cars.

Christie's auction house has an entire department dedicated to "vintage couture and luxury handbags." Business is booming.

A Christian Dior evening gown with matching handbag from 1968 sold for more than $360,000 at an auction in 2011. It was part of the collection of Elizabeth Taylor.

In the world of high fashion, it doesn't get much better than a gorgeous dress that has the stamp of Hollywood and a top brand.

The black satin gown by Givenchy that Audrey Hepburn wore in the film "Breakfast at Tiffany's" went for just shy of $800,000 in 2006.

"We always advise our clients to buy what they love," says Patricia Frost, director of fashion and textiles for Christie's in London. "If you are looking to buy for an investment piece however, condition is crucial and buyers should look for garments that are perfect or near-perfect and have not been altered."

Much like artists, fashion designers have different styles and phases over their lifetimes. Frost recommends buying pieces that are "synonymous with a designer and are from their most important era."

Fashion designer George Simonton has seen this trend firsthand in his long career in New York.

"There's definitely a resurgence. Couture is not just something that is frivolous, it can turn into real dollars" he says, noting that his own loyal fans follow him on Facebook and want to know about his TV appearances.

He was at the preview for Christie's auction of Elizabeth Taylor's collection in 2011.

"You have to keep [the clothes] well preserved. Elizabeth Taylor's clothes were beautifully kept. She hardly wore them, and she was one of the few actresses who actually paid for her gowns," he says.

Simonton is also a professor at the Fashion Institute of Technology and says many of the young designers he mentors wish more celebrities were like Taylor. Today most actresses refuse to pay for couture outfits, claiming they are giving free publicity to the designer.

The market for high-end fashion has extended beyond the elite auction houses and into the mainstream. There's been an uptick in vintage stores, especially online.

"Every little flaw in the garment will bring the price down in value, so the best you can hope for is to find dead stock that still has the tags," she notes.

She saw a spike in vintage interest this time last year when "The Great Gatsby" remake came out and people were throwing 1920s themed parties and weddings. "That stuff is almost 100 years old. You just can't find it, and when you do, it's really expensive."

While couture isn't fetching multimillion dollar prices yet like art, it might only be a matter of time.